Baja Runner
Member
:reddance::reddance:
Funny, I was going to PM you and ask!!
Funny, I was going to PM you and ask!!
Engine cranks 3 times too long
- Thread starter Gerdo
- Start date
Rockdawg84
New member
What is interesting is that I have been watching to see what your fix was. Congrats!!! I replaced my fuel pump a while back with my 7th injector setup. And since then my cold starting takes forever. Lol. So much for a high flow pump. Lol
Drcoffee
Senior Member
Vapor lock
Years ago when the cars first started getting these new fangled fuel injectors the cars would have this very same issue of difficult warm starts. Some worse than others. It was a case of VAPOR LOCK. The engineers ran the fuel lines too close to the engine and on shut down the heat would vaporize the fuel inside the fuel rail. This caused an air pocket and on subsequent start up the fuel pump had to push all the air out before it would fire up, if it would at all. Since then the fuel pumps have gotten better and stronger as well as designing the rails so that they don't soak up all the heat from the engine. I would think that the 3.4 drivers side would be the likely culprit when the fuel pump starts to weaken since it is tucked under the intake and captive to the heat from the engine.
I was going to suggest that you insulate the fuel rail to test it but the end result would have been the fuel pump anyway.
Years ago when the cars first started getting these new fangled fuel injectors the cars would have this very same issue of difficult warm starts. Some worse than others. It was a case of VAPOR LOCK. The engineers ran the fuel lines too close to the engine and on shut down the heat would vaporize the fuel inside the fuel rail. This caused an air pocket and on subsequent start up the fuel pump had to push all the air out before it would fire up, if it would at all. Since then the fuel pumps have gotten better and stronger as well as designing the rails so that they don't soak up all the heat from the engine. I would think that the 3.4 drivers side would be the likely culprit when the fuel pump starts to weaken since it is tucked under the intake and captive to the heat from the engine.
I was going to suggest that you insulate the fuel rail to test it but the end result would have been the fuel pump anyway.
DirtDawg
New member
So if anyone is still following this thread, the issue is the fuel pump, we all know that. But the even more pinpointed issue is that inside the fuel pump there is a backflow valve. It controls gas flowing back in the tank. Well on these older cars,mthat valve, or gasket, wears down rendering it useless. So the solution is still to replace the pump, just thought id share this with yall.
-DirtDawg
-DirtDawg
Whelp love to resurrect this thread ... I have a 2006 4runner with 160k. Posting this here because although this is the 3rd gen forum my problem is most similar to Gerdo's of the threads I've read.
Problem: 5 second crank when engine is hot. Starts fine when cold.
Back story: Driving from TN to CO I woke up in Kansas and it was -10. For the first time since I've owned the truck (5k miles) it had a longish crank. Got home and the problem of a long crank on cold starts persisted. At this point it was fine when starting warm. I thought it was a fuel pump problem and in fact the fuel pump was not holding pressure, so I had the fuel pump replaced. The mechanic tested and confirmed that the fuel pump was now holding pressure. I also replaced the spark plugs. Then it started to have intermittent long cranks when it was warm (sometimes it would fire right away other times it would take up to 5 seconds). Now it always has long cranks (5 seconds when fully heated, shorter but long when somewhat warm, and right away when cold). Also, now if I turn the key - turn off - rinse and repeat x3 to prime the fuel system, I still have a long crank.
To summarize: it's not the fuel pump or the spark plugs. Any ideas or threads to look at?
Problem: 5 second crank when engine is hot. Starts fine when cold.
Back story: Driving from TN to CO I woke up in Kansas and it was -10. For the first time since I've owned the truck (5k miles) it had a longish crank. Got home and the problem of a long crank on cold starts persisted. At this point it was fine when starting warm. I thought it was a fuel pump problem and in fact the fuel pump was not holding pressure, so I had the fuel pump replaced. The mechanic tested and confirmed that the fuel pump was now holding pressure. I also replaced the spark plugs. Then it started to have intermittent long cranks when it was warm (sometimes it would fire right away other times it would take up to 5 seconds). Now it always has long cranks (5 seconds when fully heated, shorter but long when somewhat warm, and right away when cold). Also, now if I turn the key - turn off - rinse and repeat x3 to prime the fuel system, I still have a long crank.
To summarize: it's not the fuel pump or the spark plugs. Any ideas or threads to look at?
Chesshircat
New member
Check the rubber fuel line between the fuel pump and the pickup. They can deteriorate and not seal. Also the factory clamps can rust and not hold. You will have to pull the whole unit from the tank, check both hoses at the fuel pump. Replace with new line and hose clamps. When this happens you lose pressure and will have to crank longer to build pressure back.
In my experience with other cars, - problems starting when warm had to do with the crankshaft position sensor. I don't know in the 4Runner, but I've seen people recommend checking O2 sensors and etc, but as far as I know, O2 sensors are more for informing your fuel injection system during actual running, not startup, but I'm not a mechanic so who knows.
If your fuel pump has the proper pressure, I'd start checking the sensors having to do with startup.
Another thing I read in some threads here - and this was for COLD startup, not warm, was that the charcoal canister can go bad. I would think this would throw a code, but for this person, replacing the canister fixed their issue.
Utah_4runner
New member
I have another thread going with this issue, but did you ever find a solution? I am battling the same thing.
St Runner
Member
I would double check your grounds and upgrade them if you can. I have had this problem with my 86 tacoma and my 99 tacoma. On my 86 it was the computer that needed extra grounding and on my 99 I ran an extra ground from the engine block to the frame and back up to the battery. Cold starts all the wires have more capacity but when they get warm they cannot run as much current. If your ground is maxed out when you are using your starter, all the other sensors that need a good ground to function properly don't work as well. When it is hot take a set of jumper cables and run them from the engine block and body to the negative battery terminal, if it fires right up its your ground
Jeremy556
New member
Just replaced the fuel pump in my 5th gen for this same reason. Started fine when cold, or re-started within a couple minutes of stopping. If it was hot and left for 20+ minutes it would take 3-8 seconds to fire.
Disconnecting the inbound fuel line near the rail had no pressure after sitting for a while, so I knew it was leaking somewhere. I initially discounted the check valve because it started fine when cold. I guess the fuel injector pulse width is much wider when cold, allowing the air in the line out and gas to make it to the cylinders quicker than when hot, hence it starts fine when cold
Narrowed it down to the check valve by clamping the inbound fuel line with vice grips just after shutting down, waiting 30 minutes and re-starting. It fired right up, then of course stumbled as the fuel in the rail was depleted.
I also noticed that the pump has no sort of priming, it doesn't run until the engine is spinning.
Disconnecting the inbound fuel line near the rail had no pressure after sitting for a while, so I knew it was leaking somewhere. I initially discounted the check valve because it started fine when cold. I guess the fuel injector pulse width is much wider when cold, allowing the air in the line out and gas to make it to the cylinders quicker than when hot, hence it starts fine when cold
Narrowed it down to the check valve by clamping the inbound fuel line with vice grips just after shutting down, waiting 30 minutes and re-starting. It fired right up, then of course stumbled as the fuel in the rail was depleted.
I also noticed that the pump has no sort of priming, it doesn't run until the engine is spinning.
Renegade_Medic
New member
I had this issue and the fuel pump (Denso) didn't help. Try replacing the MAF sensor first. Fixed it immediately for me. Cleaning it didn't do anything, it had to be outright replaced, with Denso of course.
OrRunner
New member
I recently replaced the fuel pump on my 2002 t4r to correct a long crank when cold, typically 2-3 seconds. While I’m not upset that I have a new fuel pump rather than the 200k original, the starting appears to be exactly the same following replacement. The vehicle is in excellent mechanical condition, used motor has about 125k on it, new plugs new fluids maf/throttle body clean as a whistle. Vehicle runs and drives perfectly, it just has an unusually long cold start. Anyone have an idea of where to go from here? I understand there is a fuel pressure regulator with a check valve that could be the culprit? My next stop might be to do the big 3 electrical upgrade and check for loose grounds, but the vehicle has all stock electronics and no current electrical issues, so I’d rather not get into it unless there is a good reason to do so.
Edit: what prompted me to swap the fuel pump was a dead battery. I swapped the battery after attempting to start it a few times, and noticed it fired on the first crank when I got the new battery in. Made me think there was enough juice with the old battery to fire the fuel pump but not to turn the starter, allowing it pressurize the system.
Edit: what prompted me to swap the fuel pump was a dead battery. I swapped the battery after attempting to start it a few times, and noticed it fired on the first crank when I got the new battery in. Made me think there was enough juice with the old battery to fire the fuel pump but not to turn the starter, allowing it pressurize the system.
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Renegade_Medic
New member
No matter how clean your MAF appears, if it's old, just replace it. I jacked around with different things on mine and that's what fixed it for me. It was rich on start ups and a little puff of black smoke would shoot out when it did it.
